debris extrusion comparison

8/3/2019 Debris Extrusion Comparison

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0 0 9 9 - 2 3 9 9 / 9 1 ] 1 7 0 6 - 0 2 7 5 / $ 0 3 . 0 0 / 0JOURNAL OF ENDODONTICSC o p y r i g h t 9 1 9 9 1 b y T h e A m e r i c a n A s s o c i a t i o n o f E n d o d o n t is t s Printed in U.S.A.VOL. 17, NO. 6 , JUNE 1991

A Comparison of Weights of Debr is Extruded Apical lyby Convent iona l F i l ing and Can al M aster Techn iquesG a r r y L. M y e r s , D D S , a n d S t e v e M o n t g o m e r y , D D S , F A C D

S i x t y e x t r a c t e d h u m a n t e e t h w e r e d i v i d e d i n t o t h r e eg r o u p s o f 2 0 e a c h . A p i c a l l y e x t r u d e d d e b r i s a n di rr i g an t w e r e c o l l e c te d , d r i e d , a n d w e i g h e d b y t h ef o l l o w i n g t h r e e i n s t r u m e n t a t i o n t e c h n i q u e s : ( a )g r o u p 1 , f i li n g 1 m m s h o r t o f t h e f o r a m e n ; ( b ) g r o u p2 , C a n a l M a s t e r i n s t ru m e n t a t i o n t o th e f o r a m e n ; a n d( c ) g r o u p 3 , f i l i n g t o t h e f o r a m e n ( f o r a r e l a t i v ec o m p a r i s o n ) . T h e r e s u l t s i n d i c a t e d t h a t a l l t h r e eg r o u p s w e r e s i g n i f i c a n t l y d i f f e r e n t f r o m o n e a n o t h e r .G r o u p I h a d t h e l e a s t a m o u n t o f d e b ri s e x t r u d e d . O ft h e t w o g r o u p s i n s t r u m e n t e d t o t h e f o r a m e n , g r o u p3 h a d t w i c e a s m u c h d e b r i s e x t r u d e d a s g r o u p 2 . A na p i c a l d e n t i n a l p l u g w a s f r e q u e n t l y f o u n d i n g r o u p 1a n d w a s p r o b a b l y a m a j o r r e a s o n w h y t h i s g r o u ph a d t h e l e a s t a m o u n t o f e x t ru d e d d e b r is . T h e s i g n if -i c a n c e o f t h i s d e n t i n a l p l u g a n d p o s s i b l e i n d i c a t i o n sf o r in s t r u m e n t a ti o n t o t h e f o r a m e n a r e d i s c u s s e d .

T h e f l ar e -u p p h e n o m e n o n d u r i ng e n d o d o n t i c t r e a t m e n t h a sb e e n a p e r s is t e n t p ro b le m o v e r th e y e a rs (1 -6 ) . I t i s m o s to f ten as soc ia ted with pa in and swel l ing during o r a f te r com-p le t ion o f roo t cana l the ra py . Se l tze r and Na ido rf (1 ) d iscussedsevera l fac to rs tha t poss ib ly t r igger th is p rocess , inc lud ing : (a )a q u ie s c e n t c h ro n ic in f l a m m a to ry p e r i a p ic a l l e s io n w h ic hreac ts v io len t ly whe n ro o t cana l the rap y is in i t ia ted an din t ro d u c e s in fe c t iv e d e b r i s i n to th e l e s io n a n d (b ) im m u n o -lo g ic a l p h e n o m e n a , e i th e r c e l l m e d ia t e d o r h u m o ra l , t h a tr e s p o n d to fo re ig n m a te r i a l o r a n t ig e n s in th e a re a . N a id o r f(2) a ls o p o s tu l a te d th a t a c e r ta in m in im a l a m o u n t o f in o c u lu mis needed to in i t ia te these types o f responses . Ing le and Bev-e r id ge (3) i l l u s tr a t e d a " w o rm " o f n e c ro ti c d e b r i s w h ic h w a sfo rc e d th ro u g h th e fo ra m e n o f a n in s t ru m e n te d to o th . T h e ys ta t e d th a t t h i s m a te r i a l p o te n t i a l ly c o n ta in e d m i l l i o n s o fbac te r ia which w ould ac t a s a n idus fo r an acu te ap ica l abscess.

O v e r th e p a s t 2 0 y r , a n u m b e r o f s tu d ie s h a v e c o n f i rm e dth a t d e b r i s i s i n d e e d fo rc e d o u t t h e a p ic a l fo ra m e n d u r in gc a n a l i n s t ru m e n ta t io n a n d th a t s o m e in s t ru m e n ta t io n t e c h -n iques may ex trude le s s mate r ia l than o the rs (5 -10) . In 1968 ,Ch apm an e t a l. (5) ve r i f ied the expu ls io n o f in fec t ive mate r ia lf ro m th e ro o t c a n a l s y s t e m d u r in g e n d o d o n t i c i n s t ru m e n ta -t ion . In tha t same year Se l tze r e t a l. (6 ) showed tha t pe r iap ica lt i s s u e r e a c t io n s o c c u r re d w h e th e r i n s t ru m e n ta t io n w a s c o n -

f in e d w i th in th e c a n a l s p a c e o r w a s e x te n d e d b e y o n d th ea p ic a l fo ra m e n . In 1 9 7 5 , V a n d e V i s s e a n d B r i l li a n t (7 ) d e m -o n s t r a t e d th a t i n s t ru m e n ta t io n w i th i r r ig a t io n p ro d u c e d s ig -n i f i c a n t ly m o re e x t ru d e d d e b r i s t h a n d id in s t ru m e n ta t io nw i th o u t i r r ig a t io n . H o w e v e r , o th e r i n h e re n t p ro b le m s e x i s t e dw i th d ry in s t ru m e n ta t io n a n d i r r ig a tio n w a s d e e m e d e s s en t ia l .In 1 9 8 2, M a r t in a n d C u n n in g h a m (8 ) s h o w e d th a t e n d o s o n icin s t ru m e n ta t io n p ro d u c e d l e ss a p ic a lly e x t ru d e d m a te r ia l t h a nd id h a n d f il in g. F o u r in s t ru m e n ta t io n t e c h n iq u e s w e re c o m -pared by Fa irb ourn e t al . (9 ) in 1987 to as sess debris ex trus iond u r in g in s t ru m e n ta t io n . T h e y fo u n d th a t s o n ic , u l t r a s o n ic ,and ce rv ica l f la r ing techn iques p roduced les s ap ica l debrise x t ru s io n th a n d id a c o n v e n t io n a l h a n d in s t ru m e n ta t io n t e c h -n ique . Ruiz -Hubard e t a l . (10) , in an ex trus ion s tudy withs i l icone mode ls , found tha t a c rown-down pressure - les s in -s t rumenta t ion techn ique had s ign if ican t ly le s s ap ica l debrise x t ru s io n th a n d id a t y p ic a l s t e p -b a c k t e c h n iq u e . T h e r e c e n ts tu d y o f Mc K e n d ry (1 1 ) in d ic a t e d th a t a n e n d o s o n ic t e c h -n ique ex truded s ign if ican t ly more debris than d id the "ba l-a n c e d fo rc e " t e c h n iq u e . O n e c o m m o n th e m e th ro u g h e a c h o fthese s tud ies was tha t , desp i te the techn ique , in the p resenceof i r r igan t , some debris was a lways ap ica l ly ex truded .R e c e n t ly a n e w ro o t c a n a l i n s t ru m e n t , t h e C a n a l Ma s te r(CM ) (12) , was in t roduced . T wo aspec ts o f i t s un ique des ignare a reduced cu t t ing segment ( f rom 16 .0 to 1 .0 to 2 .0 mm)and a th inner , sm ooth , cons tan t-d iam ete r , f lex ib le sha f t .T h e s e tw o v a r i a t io n s f ro m th e p re v io u s in s t ru m e n t d e s ig ncou ld conce i vab ly fac i li ta te debris rem ova l in a corona l d i rec -t io n , t h e re b y r e d u c in g th e a m o u n t o f m a te r i a l p u s h e d a p ic al ly .T o d a te , n o s tu d ies h a v e b e e n d o n e to d e t e rm in e th e a m o u n to f d e b r is e x t ru s io n w i th th i s i n s t ru m e n t .

T h e p u rp o s e o f t h e s tu d y r e p o r t ed h e re w a s to c o m p a re th ea m o u n t o f a p ic a l d e b ri s e x tru s io n a n d th e f r e q u e n c y o f p lu gfo rm a t io n d u r in g b io m e c h a n ic a l i n s t ru m e n ta t io n b y u s in gtwo d iffe ren t techn iques : (a ) conven t iona l hand f i l ing withFlex-R f i le s in a s tep-back fash ion and (b ) ro ta ry moti ons withC M in s t ru m e n t s .

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M A T E R I A LS A N D M E T H O D SSpecimen Selection

S ix ty e x t r a c te d h u m a n t e e th w i th m a tu re a p ic e s w e re u s e d.T e e th w e re l im i t e d to m a x i l l a ry l at e ra l i n ci s o rs a n d m a n d ib -u la r p rem ola rs wi th a s ing le cana l an d a s ingle ap ica l fo ramen .


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276 Myer s and MontgomeryThis was ver i fied by viewing thei r radiographs a nd examiningthem und er a s tereomicroscope. Next , the fol lowing measure-ments w ere mad e an d recorded: (a) the degree of apicalcurvatures , by us ing the meth od of Schneider (13) ; (b) theest imated canal lengths (CL) as measured f rom the radio-graphs; (c) the largest diameter and (d) the smallest diameterof the apical foramin a m easured by u s ing a s tereomicroscopewi th a screw micrometer eyepiece. These four cr i ter ia werecovar iates and were submit ted to a s ta t i s t ic ian who enteredt hem i n t o a comp ut e r whi ch r ando ml y as s i gned t he t ee t h t oone o f three grou ps (20 each) whi le keep ing the covar iates asequal ly dis tr ibuted as possible am on g the groups .

The bucc al cusp/ incisal edge of each tooth was then f lat -tened as a reference point , a conv ent ion al access preparat ionwas made , and t he cana l was b roached t o r emove t he bu l k o fthe soft t issue. The roots were scaled with a currette andfur ther c leaned wi th a s t i f f #11 Rob inson br i st le brush rotat -ing in a s low-speed handpiece. CL was determined by a #8Flex-R f ile (Union Broach, New York, NY) being placed intothe canal unt i l the t ip was f lush wi th the apical foramen, arubber stop being placed flush with the flattened referencepoint , and then the dis tance f rom the s top to the f i le t ip beingmeasured.

Canal Instrumentation

Three groups were selected for this s tudy. In group 1(cont rols) , the canals were ins t rumented wi th a convent ionalf il ing techniq ue 1 mm shor t of the CL length (14, 15) . A #10Flex-R fi le was used to circumferentially fi le the canal to thepreestabli shed CL. This was then fol lowed by ci rcumferent ia lf il ing wi th # 15 through #40 F lex-R f iles 1 mm shor t of theCL. Heds t rom f iles #45 through #55 were then used in a s tep-back fashion to f i le the middle and cervical thi rds of the canal .The #40 F lex-R was placed back to the working lengthbetween each Hedst rom f i le . Before ins t rumentat ion, thecanal was f looded wi th 2 ml o f dis ti l led water and betweeneach f i le s ize an add i t ional 1 ml was del ivered throug h anendodont ic i r r igat ion needle for canal i r r igat ion. The needlet i p was p laced no c l ose r t han 8 mm f rom t he fo r amen open i ngin al l teeth, and i t was never a l lowed to bind. This sameir r igat ion proced ure was used for groups 2 and 3.

Grou p 2 was i ns t rument ed w i th CM i ns t ruments t o t he CLas directed by the videotape a nd ins t ruct ions enclosed by thema nu fac tur er (12). Init ial ly, # 10 an d # 15 Flex-R fi les wereused in a circum ferentia l ma nn er unti l the # 15 file fi t passivelyat canal length. Rotary CM #50, 60, 70, and 80, were thenused to prepare the cervical and m iddle thi rds of the canaldown t o t he curve o r t o a po i n t no c l ose r t han 5 mm f romthe apical foramen. T he apical por t ion o f the canal was thenprepared wi th CM #20 through #40 to the CL by using acont inuous 30- to 45-degree rotary mot ion in each di rect ion.A s t ep-back p rocedure i n 1 -mm i nc rement s was done byusing CM #45 through #55 wi th recapi tulaton wi th the las tapical instrument between each larger size. Irrigation withdisti l led water was used as in group 1.

Because the f i rs t two groups involved two di f ferent tech-niques and two di f ferent working lengths , a thi rd group wasused to provide a re la t ive compar ison between the two tech-niques wi th the same working lengths . Group 3 canals wereins t rumented by us ing the same f i l ing technique as in group

Journal of Endodontics1 but were ins t rum ented to the canal length, as were thecanals in group 2. I r r igat ion was accompl ished in the samefashion as in the previous groups .

Debris Collection

Each tooth was secured for ins t rumentat ion and debr iscol lect ion by the root being forced through a p recut hole in a#1 rubbe r stopper. A 15- 45- ram glass shell vial (Kimb le,Toledo, OH) was used as the col lect ing container for anydebr is or i r r igant ext ruded dur ing ins t rumentat ion. This vialwas placed into a glass flask (20-ml scinti l lat ion vial; Kimble)wi th the rubber s toppe r f i t ted securely into the mo uth of thef lask. The apex of the root was suspended below the u pperrim o f the collection vial (Fig. 1). The use of the collectionvial was a modif icat ion o f the technique u sed by Fai rb ournet al . (9) for debris collection. A 25-gauge needle was placedalongside the s topper dur ing inser t ion to equal ize the ai rpressure inside and outside the flask. The flask was then heldsecurely in a rubber- jawed vise, and a rubber da m was placedto obscure the f lask so that the root could not be observeddur ing ins t rumentat ion. Al l ins t rumentat ion was done by thesame person. Af ter canal ins t rumentat ion, any deb r is visual lyadherent to the root end was scraped off wi th the inn er edgeof the col lection vial and the root apex was f lushed wi th 0.1ml o f dist il led w ater to wash any rema ining deb r is into thevial. O nce the debr is was remo ved f rom the roo t surface, thepresence of an apical plug was determined by viewing theforamen area through a s tereomicroscope.

Unexpectedly, a s igni ficant amou nt of i r rigant was f re-quently present in the collection vials. A clean vial was fi l ledwi th i r r igant in 0.5-ml increments and marked at each level .The v olume of ext ruded i r r igant was measured by placing thecollection vials next to this calibrated vial . The vials were thenimmediately placed into a dessicator (with CaC12 crystals) todr ive off a ll mois ture before a dry weight was obtained. Thedess icator was kept in a warm roo m (85~ unt i l the vialswere dry and was then kept a t room temperature for 24 hbefore the final weighing.

FIG 1. Toot h in stopp er (a), collection vial (b), flask (c), and ve nt (d)before assembly.


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Vol. 17, No. 6, June 1991Weighing Debris

The collection vials were cleaned, labeled, dessicated overCaC12 for 24 h, and brou ght to constant weights before beingused as collection devices. All weighing was don e on a Mettlerbalance (model #H54AR; Met t ler Ins t rument Corp. , Hights-town , N J), and at least two weights were record ed b efore andaf ter debr is col lect ion to ver i fy that a cons tant w eight wasachieved. The vials were handled wi th clean cot ton forceps atall times.

S ix cont rol vials were taken by the same precol lect ionprocedures as out l ined above. Two to three mi l l i l i ters ofdistil led water were placed in eac h of these, and they werethen dried an d weig hed to see if the dist i lled water (used asthe irrigant) left any residue.

Statistical AnalysisT he m ean dry we i gh ts o f t he t h ree g roups were compared

to determ ine i f any s igni ficant di fferences exis ted a mo ngthem. S ingle- factor analys is of var iance an d S tudent -New-man-Keuls procedures were used to evaluate the data .

R E S U L T SDebris Extruded

Of the 60 teeth used in this s tudy, two had to be discardedbecause a #8 f i le could not be placed to the foramen beforeins t rumentat ion. The m ean dry weights and the range ofdebr is col lected for each group are presented in Table 1.Accord ing to analys is of var iance, the di f ference amo nggroups was s ignif icant (p = 0.0001). Fu r thermore , the S tu-dent -Newman-Keuls tes t showed that a l l three groups weres igni ficant ly di fferent f rom one another a t the 0.05 level . Thegroup ins t ru mented shor t of the foramen ha d s igni f icant lyless debris ext ruded then the other two groups . O f the twogroups i ns trument ed t o t he fo r amen , t he CM g roup ex t rudedsignificantly less debris.

Apical Plug FormationApical plugs were seen in 16 of 19 (84.2%) teeth instru-

men ted 1 mm shor t of the foram en whereas they were seenin only 4 of 39 (10.3%) teeth ins t rum ented to the foram en.Al l four of the la tter group occurred in teeth wi th an abruptapical curve which may not have been ins t rumented wi th thelarger file sizes.

The two diameters o f the apical foramina, the canal lengths ,and canal curvatures were al l considered as covar iates in thisstudy (Table 2). A stepwise regression analysis showed thatonly the CL had a s igni f icant correlat ion wi th the amount ofdebr is ext ruded ( longer CL, m ore ext rus ion). Howe ver , s incethe CL group mean s di f fered very s light ly, the resul t s of thes igni f icance tes t s among groups remained unchanged. In ad-di t ion, no s igni f icant di f ference was noted when compar ingthe two types of teeth used wi thin each group.

Som e samples in each of the three groups had som e i r r igantpresent in the collection vial after instrumentation (Fig. 2).The major i ty of these occurred in the two groups ins t ru-

Apically Extruded Debris 277mented the ent i re length of the canal (Table 3) . Al though acorrelat ion was suspected between the v olume of i r r igantcollected and the final mean dry weights, statist ical analysisshowed otherwise-- there was no s igni f icant correlat ion be-tween these two observat ions .

ControlsOf the six dist i lled water controls , f ive of the co llectionvessels weighed within -+0.01 mg before and after the irrigant

TABLE 1. Extruded debris (mg) and apical plugsGroup n* Mean SD Range Plugs

1 (Fil ing 1 mm 19 0 .2 2_ 0.17 0,01-0.69 16short)2(CM) 20 0.78_+0.40 0.01-1.74 13(Fil ing to foramen) 19 1. 58 _ 1.16 0.14-4.02 3* To ta~ numb er o f tee th i n each group.

TABLE 2. Mean valu es for covar iates by group

GroupApical Foramina CanalLargest Smallest CL CurvatureDiameter Diameter (m m) (degree s)(mm) (mm)

1 0.33 0.26 20,9 14.52 0.33 0.26 21,1 16,33 0.33 0.23 20.9 12.3

FtG 2. A drop of irrigant (a) suspended from the apical end of the roo tin the assembled apparatus before falling into the collection vial (b).Flask (c).

TABLE 3. Collec ted irrigant by groupNo. of Mean Volume RangeGroup Samples (ml) (ml)

1 5 0.79 0.50-1 .502 13 2,25 0.30-5.203 17 1.77 0.20-3 .70


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278 Myers and Montgomeryw a s p l a c e d . T he s i x t h w e i ghe d 0 . 03 m g he a v i e r a f t e r t hei r r i ga n t w a s d r i e d ou t . T he s e f i nd i ngs i nd i c a t e d t he i r r i ga n td i d no t c on t r i bu t e a ny s i gn i f i c a n t r e s i due t o t he d r y de b r i swe ight s .

D I S C U S S I O N

T he r e s u l ts o f t h is s t udy a p pe a r t o c o r r e l a t e w e ll w i th t hos eo f p r e v i ou s de b r i s e x t r u s i on s t ud i e s ( T a b l e 4 ). T h r e e p r e v i ouss t ud i e s ( 8 , 9 , 11 ) e a c h i nc l ude d a g r ou p f i le d 1 m m s ho r t o ft h e C L . T h e r e s u lt s f o r t h is g r o u p r a n g e d f r o m a m e a n l o w o f0 . 22 m g ( t h is s t udy ) t o a m e a n h i gh o f 0 . 53 m g ( 8 ) . T he s ed i f f e re nc e s m a y be a t t r i bu t e d t o a va r i e t y o f f a c to r s , i nc l ud i ngo p e r a t o r t e c h n i q u e , d e b r i s c o l l e c t i o n m e t h o d o l o g y , a m o u n to f ap i c a l i n s t r um e n t a t i o n be f o r e c o l l e c t i on o f de b r is , s i ze a ndtypes o f fi le s used, e t c . Desp i t e the se v a r i able s , t he r e sul t sa ppe a r r e a s ona b l y c ons i s t e n t .

O n l y one p r e v i ous s t udy ( 8 ) ha s i nvo l ve d de b r i s c o l l e c t i ond u r i n g i n s t r u m e n t a t i o n t o o r b e y o n d t h e f o r a m e n . A s i n th es t u d y p r e s e n te d h e re , t h e a m o u n t o f e x t r u d e d d e b r i s w a ss i gn i f i c a n t l y h i ghe r w he n t he e n t i r e C L w a s i n s t r um e n t e d . I nt he s t udy r e po r t e d he r e , g r e a t c a r e w a s u s e d t o i n s t r um e n t t ot h e f o r a m e n ( a n d n o t b e y o n d t h i s p o i n t ) i n g r o u p s 2 a n d 3 .W h e n t h e s e g r o u p s w e r e c o m p a r e d , t h e C M t e c h n i q u e r e -s u i t ed i n s i gn i f i c a n t ly l e ss de b r i s e x t r u s i on t ha n d i d t he f i li ngt e c hn i que . T h i s d i f f e r e nc e m a y pe r ha ps be a t t r i bu t e d t o t hede s i gn fe a t u r e s o f t he C M i ns t r um e n t s . T h e s m a l l e r c u t t i nghe a d p r oba b l y p r oduc e s l e s s de n t i na l de b r i s t ha n d i d a c on -ve n t i ona l f i l e . A dd i t i ona l r oom p r ov i de d by t he r e duc e d s ha f tm a y f a c i li t a te t he r e m o va l o f de n t i na l de b r i s f r om t he c u t t i ngf lu t e s. A vo i d i ng c l ogge d f lu t e s m a y , t he r e f o r e , a i d i n r e duc i ngt h e a m o u n t o f d e b ri s p h y s ic a l ly p u s h e d f o r w a r d i n t h e c a n a l.T h e u s e o f f il in g m o t i o n s a s o p p o s e d t o r o t a r y m o t i o n s m a yh a v e b e e n a n o t h e r f a c t o r d e t e r m i n i n g t h e a m o u n t o f e x t r u d e dde b r is . Fu r t he r r e s e a r ch i s ne e de d t o s e e if i n s t r um e n t de s i gno r i n s t r u m e n t a t i o n t e c h n i q u e h a s a g r e a t e r im p a c t i n t h isa rea .

A n o t h e r o b s e r v a t i o n n o t e d i n s o m e s t u d ie s w a s a p o ss ib l ec o r r e la t i o n b e tw e e n C L a n d t h e a m o u n t o f e x t r u d e d d e br is .T h i s obs e r va t i on w a s no t e d i n s t ud i e s w h i c h i nvo l ve d i n s t r u -m e n t a t i o n s h o r t o f th e f o r a m e n ( 7 , 9 ). H o w e v e r , i n n e i t h e r o ft he s e s t ud i e s w a s t h i s c o r r e l a t i on f ound t o be s t a t i s t i c a l l ys i gn i f i c a n t . I n t he s t udy p r e s e n t e d he r e , t he c o r r e l a t i on wasf o u n d t o b e s i g n i fi c a n t a n d m a y h a v e b e e n a t tr i b u t e d t o t h ef a ct th a t i n s t r u m e n t a t i o n o f tw o o f t h e t h r e e g r o u p s w e n t t ot h e f o r a m e n .

M c K e n d r y ( l 1 ) n o t e d t h a t t h e r e a p p e a r e d t o b e a f e wi ns t a nc e s w he r e t he a m ou n t o f de b r i s e x t r ude d i s s ubs t a n t i a ll y

Journal of Endodonticsl a r ge r t ha n t he m e a n a m ou n t s o bs e r ve d . Som e s t ud i e s de l e t e dthese va lues f rom the s t a t i s t i c a l ana lys i s a s out l i e r s (9 , 11)u n d e r t h e a s s u m p t i o n t h a t t h e d a t a f o l lo w e d a n i d e a l n o r m a ld i s t r i bu t ion . H ow e ve r , be c a us e o f t he c ons i s t e n t p r e s e nc e o ft he s e ou t l i e r s t h r oughou t t he s e s i m i l a r s t ud i e s , t he da t a m a yno t o c c u r i n s uc h a n i de a l d i s t r i bu t i on . I n t h i s s t udy , a l l da t aw e r e i nc l ude d f o r s t a ti s ti c a l a na l y s i s f o r t h i s r e a s on . Pe r ha ps ,a s M c K e ndr y no t e d , t he f e w c l i n i c a l f l a r e - ups t ha t oc c u r m a ybe cor re l a t ed to the exces s ive debr i s i n the se f ew out l i e r s .A n i n te r es t in g o b s e r v a t i o n w a s t h e a m o u n t o f i rr i g an tw h i c h pa s s e d t h r ou gh t he c a na l i n t o t he c o l l e c ti ng ves se l. A nobs e r va b l e a m ou n t o f i rr i ga n t w a s se e n i n 30 o f 39 ( 76 . 9% )c a na l s i n s t r um e n t e d t o t he f o r a m e n , w he r e a s i t w a s s e e n i non l y 5 o f 19 ( 26 . 3% ) c a na l s i n s t r um e n t e d s ho r t o f t he f o r a -m e n . T h i s m a y h a v e b e e n a t t r i b u t ed t o : (a ) a b s e n ce o f a na p i c a l p l ug o r n a t u r a l bo ne / t i s s ue ba r r ie r ; ( b ) t he e n t i r e c a na lbe i ng ke p t pa t e n t t o t he f o r a m e n ; a nd ( c ) g r a v i t y c a r r y i ngi r r i ga n t ou t t h r ough t he f o r a m e n i n t he i n v i t r o de s i gn u s e d .V o l um e s o f i r r iga n t a s h i gh a s 3 .5 t o 5 . 0 m l w e r e c o l l e c t e d i ns o m e s p e c i m e n s. T h e a m o u n t o f i rr i ga n t t h a t p a s se s o u tt h r ough t he f o r a m e n i s no t know n c l i n i c a l l y . Sa l z ge be r a ndBr i l l i ant (16) found in an in v ivo s tudy tha t : ( a ) i n v i t a l c a se s ,t h e i r ri g a n t w a s f o u n d o n l y i n t h e s p a ce c r e a te d b y i n s t r u m e n -t a t i on w he t he r i t w a s c on f i ne d t o t he c a na l s pa c e o r w he t he ri t e x t e nde d i n t o t he pe r i a p i c a l a r e a a nd ( b ) i n ne c r o t i c c a s e s ,t he i r r i ga n t w a s no t ne c e s s a r i l y c on f i ne d on l y t o t hos e a r e a sw h i c h h a d b e e n i n s t r u m e n t e d . W h e n i t d i d p e n e t ra t e i n t o t h epe r i a p i c al t is sue s, t he i r r i ga n t a ppe a r e d t o be r a nd om l y d i s -t r ibuted in the apica l l e s ion. C l in i ca l ly then , t he t i s sues sur -r ound i ng t he a pe x a ppe a r t o a c t a s a na t u r a l ba r r i e r , s o onem u s t w o n d e r h o w m u c h d e b r i s a c t u a l l y p a s s e s o u t i n t o t h epe r i r a d i c u l a r t i s s ue s w he n t he c a na l i s i n s t r um e n t e d t o t hef o r a m e n . W ou l d t h i s ba r r i e r be e qua l l y e f f e c t i ve a ga i n s t t hec o m p a c t e d w o r m o f d e b r i s fo r c e d o u t w h e n i n s t r u m e n t a t i o ni s s ho r t o f t he f o r a m e n? I f bo t h s i t ua t ions r e s u l t e d i n e x t r ude dm a t e r i a l , w h i c h s c e na r i o w ou l d be ha nd l e d be t t e r by t hepe r i a p i ca l t i s s ue s - - de b r i s s u s pe nde d i n i rr i ga n t o r de b r i s c om -pa c t e d i n t o a c onde ns e d m a s s , i . e . , t he a p i c a l w or m ?

A r e a s s e ss m e n t o f t he a p i c a l de n t i na l p l ug s hou l d be c on -s id e re d . D u r i n g i n s t r u m e n t a t i o n , n e i th e r m e t h o d g a v e a n yi nd i c a t i on i f p l ug f o r m a t i on w a s oc c u r r i ng . I n a s ho r t - t e r ms c e na r io , t he be ne f i t s o f t h i s p l ug a ppe a r n um e r ou s : i t s e e m st o l i m i t th e a m o u n t o f d e b ri s w h i c h i s e x t r u d e d , t h e r e b yr e duc i ng t he c h a nc e s o f po t e n t i a l f la r e -ups , i t p r oba b l y p r e -ve n t s ove r i n s t r u m e n t a t i on o f t he pe r i a p ic a l t is s ues , a nd i tp r o b a b l y h e l p s to p r e v e n t t h e e x t ru s i o n o f th e o b t u r a t i n gm a t e r i al s . L o ng- t e r m p r ognos i s , how e ve r , c ou l d po s s i b l y bec om pr om i s e d , e s pe c i a l ly i n te e t h w i t h ne c r o t i c pu l p s , be c a us e

TABLE 4. Comp arison of extrusion studies*F i l i n g U l t r a s o n i c S o n i c O t h e r F i l i n g C M

V a n d e V i s s e - - - 0 . 4 1 1 - -F a i r b o u r n 0 . 3 0 0 . 2 0 0 . 1 2 0 . 1 8 1 : - -M a r t i n 0 . 5 3 0 . 2 2 - - 1 . 3 9 8 2 -M c K e n d r y 0 . 4 6 0 . 6 0 - 0 . 2 5 w -M y e r s 0 . 2 2 - - - 1 . 5 8 8 2 0 . 7 8 8 2

* V a l u e s a r e m i l l i g r a m s of de br is .1" 1 /4 u rn and pu l l .: l : Ce rv i ca l f l a r i ng .w B a l a n c e d f o r c e .8 2 n s t r u m e n t a t i o n t o f o r a m e n .


5/5

Vo l . 17 , No . 6 , Ju n e 1991t he p l ug i s i n s i de o f t he c a na l w he r e i t is d i ff i c u l t f o r hos tde f e ns e s to r e m ove i t.

H o l l a nd e t al . ( 17 ) s how e d t ha t i f i n f e c t ed de n t i n c h i p s a r ea c c um ul a t e d be t w e e n t he f i ll ing m a t e ri a l a nd t he pe r i a p i c a lt i s s ue s , t he he a l i ng p r oc e s s m a y be i m pa i r e d . R oo t c a na l sp l u g g e d w i t h c o n t a m i n a t e d d e n t i n c h i p s re s p o n d e d m u c hm o r e poo r l y t ha n d i d c a n a l s w he r e p l ugs w e r e a bs e n t . S t ud i e si nvo l v i n g v it a l pu l p s ha ve s ho w n f a vo r a b l e r e s u lt s ( 18 - 20 )w he n a n a p i c a l p l ug w a s c r e a t e d . I t w a s f ound t ha t : ( a )p l ugg i ng o f t he c a na l w a s f a ir l y e as i ly a c c om pl i s he d ( 18 ) ; ( b )f e w e r i n s ta n c e s o f p e r ia p i ca l i n f l a m m a t i o n o c c u r r e d w h e np l ugs w e r e f o r m e d ( 19 ); (c ) p l ugs p r ov i de d a n e f f e c ti ve ba r r i e ra ga i n s t w h i c h t o ob t u r a t e ( 20 ) ; a nd ( d ) a c a lc i fi c ba r r i e r w i t ha n a p p e a r a n c e s i m i l a r t o c e l l u l a r c e m e n t u m c o u l d d e v e l o pa d j a c e n t t o t he s e a p i c a l p l ugs ( 20 ). F o l l ow - up p e r i ods i n t he s es t ud i e s r a nge d f r om 95 da ys t o 12 m o n t hs . W hi c h t he n , i s am o r e de s i r ab l e e nd r e s u lt : ( a ) a c a na l i n s t r um e n t e d s ho r t , w i t ha n a p i c a l p l ug a nd pos s i b l y a low e r i nc i de nc e o f t r e a t m e n t -r e l a t e d f l a r e - ups o r ( b ) a c a na l i n s t r um e n t e d t o t he f o r a m e nw i t h no p l ug a nd pos s i b l y a be t t e r l ong - t e r m p r ognos i s ( a l -t h o u g h s h o r t - t e r m f l a r e - u p s m i g h t o c c u r m o r e f r e q u e n t l y ) ?T h i s i s a c l i n i c a l d i l e m m a w h i c h s hou l d be t he s ub j e c t o ffuture r e sea rch.I n ne c r o t i c ca s e s, c om p l e t e i n s t r um e n t a t i on o f t he e n t i r eC L s e e m s de s i r a b l e . F i nd i ng a t e c hn i que w h i c h e x t r ude s t hel e a st a m ou n t o f de b r i s und e r t he s e c ond i t i ons i s t he n de s i ra -b l e , a nd t he C M t e c hn i que a ppe a r s t o be a s i gn i f i c a n t i m -p r o v e m e n t i n t h is r e g ar d . F u r t h e r s t ud i es a r e n e e d e d t o c o m -pa r e : ( a ) o t he r t e c hn i que s t a ke n t o t he f o r a m e n ; ( b ) e f f e c t s o fmu l t ip l e fo ram ina ; ( c ) e f f ec t s of d i f f e rent i r r igant s ; and (d)d i f f e re nc e s i n a n a p i c a l ba r r i e r c ons i s t i ng o f he a l t hy t i ss ue o ra pe r i apica l l e s ion.

This ar t icle is a wo rk of the United State s government and ma y be repr intedw i thou t pe rmiss ion. T he au tho r i s an emp loyee o f the Un i ted Sta tes A i r Fo rceat Lackland Air Force Base, TX. Opinions expressed therein, unless otherwisespecif ical ly indicated, are those of the author . He does not purpor t to expressv iews o f the Depar tmen t o f the A i r Fo rce o r any o the r depar tme n t o r agencyo f the Un i ted S ta tes government .

We thank Dr. Chen Yuan for stat ist ical and computer analysis and Dr. DavidCarnes for h is assistance in the research design and m ater ia ls.Dr. Myers is a resident in the Department of Endodontics, Wil ford H al l USAFMedical Center , Lackland Air Force Base, San Antonio, TX. Dr. Montg om ery isa profess or in the Graduate Division of Endodontics, Universi ty of Texas Health

Ap ica l l y Ex t r u d ed Deb r is 279Science Center , San Antonio, TX. Address requests for repr ints to Dr. SteveMontgomery, Universi ty of Tex as Health Science Center , 7703 Floyd Cur lDr ive, San Antonio, TX 78284-7892.

References1. Seltze r S, Naidor f IJ. Flare-ups in endodontics I. Etio logical factors. JEndodon 1985 ;11 :472-8 .2. Naidorf IJ. Endodontic f lare-ups: bacter io logical and imm unological

mechanisms. J Endodon 1985;11:462-4.3. Ingle J, Bever idge E . Endodontics. 3rd e d. Phi ladelphia: Lea & Febiger ,1985 :170-80 .4. Ma tus ow RJ. The f lare-up phenomenon in endodontics: a clin ical per-spective and review. Oral Surg 1988;65:750-3.5. Chapman CE, Col lee JG, Beagr ie GS. A prel iminary repor t on thecorrelation betwee n a pical infection and instrumentation in endodontics. J BrEnded Soc 1968 ;2 :7 -11 .6. Seltz er S, Soltanoff W, Sinai I , Goldenberg A , Bender lB. B io logic aspectsof endodontics. Par t I I1. Per iapical t issue reactions to root canal instrumentation.Oral Surg 1968;26:534-46, 694-7 05.7. Vande Visse JE, Br i l l iant JD. Effect of i r r igation on the production ofextrud ed mater ia l at the root apex dur ing instrumentation. J Endodon1975;1:243-6.8. Mart in H, Cunningham WT. The effect of endosonic and hand manipu-lat ion on the amount of root canal mater ia l extruded. Oral Surg 1982;53:611-3. 9 . Fa i rbourn DR, McWal te r GM, M on tgome ry S. The e f fect o f fou r p repa-ration techniques on the amount of apical ly extruded debr is. J Endodon1987 ;13 :102-8 .10. Ruiz-Hubard EE , Gutmann JL, Wagner M J. A quanti tative assessm entof canal debris forced per iapical ly dur ing ro ot canal instrumentation using tw odifferent techniques. J Endodon 1987;13:554-8.11. Mc Kendry DJ. Compar ison of balanced forces, endosonic, and step -back f i l ing instrumentation techniques: quanti f ication of extrud ed apical debris.J Endodon 1990;16:24-7.12. Wildey WL, S enia ES. A new roo t canal instrument and instrumentationtechnique: a prel iminary repor t. Oral Surg 1989;67:198-207.13. Schneider SW. A com par ison of canal preparations in stra ight andcurved root canals. Oral Surg 1971 32:271-5.14. del Rio C, Canales ML. A sophomore pre-cl in ical laboratory coursemanual. San Antonio: T he Universi ty of Texa s Health Science Center , 198 1:40 -60 . 15. Grossman LI, Ol iet S, del Rio CE. Endodontic practice. 11th ed.Phi ladelphia: Lea & Febiger , 1985:196-206.16. Salzgeber RM, Br i l l iant JD. An in vivo evaluation of the penetration ofan ir rigating solution in root canals. J Endodon 1977;3:394-8.17. Hol land R, De Souza V, Nery M J, de Me l lo W, Bernab~ P FE, Otobon iFi lho JA. T issue reactions fo l lowing apical p lugging of the roo t canal withinfected dentin chips. Oral Surg 1980;49:366-69.18. Trons tad L. Tissue reactions fo l lowing apical p lugging of the root canalwith dentin chips in monkey te eth subjected to pulpectomy. O ral Surg1978;45:297-304.19 . Pa t te rson SM, Pa t te rson SS, N ewton CW, Ka f rawy AH. The e f fect o fan apical dentin p lug in root canal preparation. J Endodon 1988;14:1-6.20. Pitts DL, Jones JE, Oswald R J. A histo logical compar ison of calciumhydroxide plugs a nd dentin p lugs used for the contro l of gutta-percha rootcanal f i ll ing mater ia l . J Endodon 19 84;10 :283-9 3.

debris extrusion comparison

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